On March 1, 2000, a structure known as the "pile fan sump" was removed from the ground where it was buried during construction of the Brookhaven Graphite Research Reactor (BGRR) more than 50 years ago. The removal of the pile fan sump and the surrounding soils is an important milestone for the BGRR decommissioning project team. While in service, the sump - a concrete box five feet wide, seven feet long, and ten feet deep - was used to collect rainwater and other precipitation. This water drained from five large fan rooms in the fan house on the hill above the sump and from the reactor's exhaust stack. The sump was a known source of contamination; sampling done early in the decommissioning project demonstrated that water had leaked from the sump to the surrounding soil. Because of the known contamination, removal of the pile fan sump was performed as a "time-critical" action, with the approval of and oversight by the U.S. Department of Energy (DOE). The document approving this removal action - titled Action Memorandum: Brookhaven Graphite Research Reactor Pile Fan Sump Removal - is included in the Administrative Record at local libraries, and on the web at http://www.bgrr.bnl.gov/docs.html. The removal process Before the sump was removed, more than 250 feet of pipe between the fan house and the sump was excavated and packaged for shipment. As the pipes were removed, they were checked for contaminants (including hazardous materials, as well as radioactive material). The soil surrounding the pipes was also checked. Some small amounts of contamination were found near two of the pipe joints, and that soil was removed. Clean soil was used to backfill the pipe excavation areas. When the sump itself was removed, some contaminated soil was found directly under the sump. The concrete sump was constructed with a one-foot-by-one-foot-by-two-foot extension on the bottom. It appears that the base of this extension was the source of leakage - possibly due to age and weathering. Approximately 300 cubic yards of soil were removed and will be shipped off site. Soil removal extended to a depth of approximately 22 feet and did not extend down to groundwater level; the soil tested clean well before that depth was reached. The decommissioning team performed real-time soil tests during the excavation. In addition, verification samples are being analyzed by the New York State Department of Environmental Conservation at an independent laboratory, and by a DOE independent verification contractor, to assure that all contamination has been removed. The sump excavation site will be refilled with clean soil. |
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| The 27,000-pound concrete sump was removed by crane and placed into a large shipping container. It will be sent to a licensed facility in Utah for disposal. |
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| Laboratory Director John Marburger and others observed the removal of the Pile Fan Sump on March 1. |